GB2337035A

GB2337035A - Containers

Info

Publication number: GB2337035A
Application number: GB9809961A
Authority: GB
Inventors: Michael Gordon Stanley; Anthony Brian Port; Andrew Mark Holden; Mark Graham Branch
Original assignee: Courtaulds Packaging Ltd
Current assignee: Albea UK Ltd
Priority date: 1998-05-08
Filing date: 1998-05-08
Publication date: 1999-11-10
Anticipated expiration: 2018-05-08
Also published as: GB9809961D0; GB2337035B

Abstract

A dispensing container has at least a portion, such as a closure 40, shoulder piece 16, or one layer of a laminated body 12, formed from a thermoplastic material containing an anti-microbial preservative. Preferred polymers for the thermoplastic material include non-polar thermoplastic resins such as polyolefin resins including inorganic fillers.

Description

l.

- 1 CONTAMRS 2337035 This invention relates to containers, in particular to dispensing containers having at least a portion made f rom thermoplastic material.

Thermoplastic materials are widely used in packaging because of their low cost and ease of forming into a variety of shapes. Thermoplastic materials are particularly suitable for the manufacture of dispensing containers where the contents of the container are expelled by deforming, typically squeezing, the container body. Such containers are used, for example, for foodstuffs, dentifrices, and medical salves and creams.

The closures of dispensing containers can become relatively unhygienic due to the build-up of previously expelled contents around the closure opening. The present invention provides a more hygienic dispensing container.

According to the present invention there is provided a dispensing container having at least a portion thereof formed from a thermoplastic material containing an ant i- microbial preservative.

The preferred polymer in the composition is a non-polar thermoplastic resin. Preferably, the non-polar thermoplastic resin is a polyolefin resin, for example a polymer derived from one or more aliphatic or aromatic alkylenes, e.g. a polymer containing units derived from at least one-of ethylene, propylene, butylene, styrene, hexene and octene. The non-polar resin may also comprise a mixture of polymers or a compound polymer. Examples of specific polyolefin resins which can be used include polyethylene, polypropylene, ethylene/propylene copolymers, and ethylene /propylene /butyl ene terpolymers. Polyethylenes are particularly preferred by virtue of their good processing and welding characteristics. The polyethylene can be low density polyethylene (density of from 0.910 to 1 T 0.925 g.CM-3), linear low density polyethylene, medium density polyethylene, linear medium density polyethylene, or high density polyethylene (HDPE) (density of from 0.950 to 0.980 g. CM-3). High density polyethylene, or a compound of high density polyethylene and linear low density polyethylene, is particularly preferred by virtue of its higher inherent barrier properties compared with lower density polyethylenes.

The preferred HDPE resin has a density of at least 0.953 g.cm-:' and a melt flow index of 4-10 g/10 min, preferably about 7- 10 g/10 min, (2160 g load at 190OC) measured to ASTM D-1238. A suitable material is available from DSM grade 7108, or BASF Lupallen 6031M.

The barrier properties of the thermoplastic material composition may be improved by the addition of an inorganic filler, preferably an inorganic platelet filler.

The invention also extends to a flexible tube container having a component formed from a composition as defined above. The tube component may be a moulded tube shoulder or closure, or a tube body including a body formed from laminate, said composition forming at least one layer of the laminate.

The platelet filler can be any of a variety of lamellar fillers, preferably one in which the platelets delaminate under shear when the filler is blended with a thermoplastics resin before processing, and more particularly when the mixture of filler and thermoplastic resin is subjected to extrusion. Suitable lamellar fillers include clays, mica, graphite, montmorillonite and talc.

Talc is a particularly preferred lamellar filler by virtue of its ease of delamination during shear. Tal c, being a naturally occurring hydrated magnesium silicate, is available in a variety of grades of greater or lesser purity. It has been found that the ease of increasing the aspect ratio of talc when it is subjected to high shear in a non-polar thermoplastic resin appears to increase as the level of impurities within the talc decreases. Thus, not only does it appear easier to delaminate the platelets of the talc, but the platelets themselves apparently resist fracture. Purer grades of talc are therefore generally preferred, since they lead to compositions which not only have good barrier properties but also have a high degree of whiteness without the necessity to include a white pigment such as titanium dioxide. The moulding composition may contain 10-30% by weight of talc, preferably about 15-06 by weight of talc.

The invention will hereinafter be described by way of example only, with reference to the accompanying drawings, in which:- Fig 1 which shows a typical construction for a flexible tubular container embodying the invention.

Fig 1 is a cross-section of one end portion of a flexible tubular container 10, having a compartment 11 for storage of contents. Compartment 11 is formed within a tubular housing 12.

The tubular housing 12 is preferably formed from a flat flexible laminate strip having a wall thickness of between 0.2-0.5 mm and comprising a laminate of several layers of different thermoplastic materials typically including a vapour impermeable barrier layer.

The laminate strip is rolled into a round or oval shape with the overlapping edges of the strip being welded together to form a round/oval cross-section flexible tube, which is subsequently cut to the desired length.

The tubular housing 12 has a shoulder piece 16 located at one end thereof having an outlet nozzle 18 for expulsion of the contents of the housing. The shoulder piece 16 may - 4 be moulded from a high density polyethylene compound. The shoulder piece 16 includes a cylindrical outer side wall 19 which is a close fit with an end portion 22 of the tubular housing 12. The upper end portion 21 of the tubular housing 5 is shaped and welded to the shoulder piece 16.

A closure 40 is fitted over the shoulder piece 16. The closure 40 has a base 41 which is secured to the shoulder piece 16 and a lid 42 which is hinged to the base 41 by hinge 43. The base 41 has an upper end wall 49 with an outer skirt 45 and an inner cylindrical wall 44 projecting downwardly from the end wall 49. The inner wall 44 has groove 46 on its inner surface which makes a snap fit connection with a bead 25 on the shoulder piece 16 to hold the closure 40 onto the shoulder piece. The end wall 49 has an aperture 47 through which the nozzle 18 projects.

The lid 42 has central annular side wall 48 which is concentric with the nozzle 18 and has an inwardly projecting annular bead 51 which is engagable with an external bead 27 on the nozzle 18 to hold the lid 42 snapped shut over the nozzle when the lid is in a closed condition as shown, and which allows the lid to be flipped up to open the container.

In order to make the container more hygienic in use, at least the closure 40, and preferably also the shoulder piece 16, is/are formed from a thermoplastic material, preferably high density polyethylene, containing an anti-microbial substance. The anti-microbial agent may, for example, be Irgasan DP 300 (M), the active ingredient of which is triclosan (3,4,41,trichloro-21-hydroxy- diphenylether), which is available from Ciba Geigy.

i 1 The anti-microbial material is mixed 25% by weight with 75% by weight HDPE to form a masterbatch. The material may be dry mixed and f ed into a dual screw extruder at about 2000C to form extruded rods which are cooled and pelletized.

- 5 The masterbatch may be used as an additive at approximately 29k weight with a high density polyethylene moulding compound for the injection moulding of shoulder pieces 16 or closures 40.

in some applications the shoulder 16, and/or the tubular housing are made from high density polyethylene which may include a platelet mineral filler to improve its barrier properties against the transmission of flavours. In such a case the Irgasan (TM) may be added to the mineral powder and dry mixed, before the addition of the filler to the high density polyethylene. Typically about 15% talc is added to the polyethylene, and the final dosage of antibacterial compound is in the order of 0.5-2%.

In some cases the laminated tubular housing 12 could be formed so that the inner laminate layer adjacent the compartment 11 contains anti-microbial preservative. Such a container is particularly useful if either the contents or the container has been made sterile.

Claims

1. A dispensing container having at least a portion thereof formed from a thermoplastic material containing an anti-microbial preservative.

2. A container as claimed in claim 1 wherein the thermoplastic material is a polyolefin.

3. A container as claimed in claim 1 or claim 2 wherein the thermoplastic material includes a powdered mineral filler.

4. A container as claimed in claim 3 wherein the filler is a talc filler which is capable of delamination under conditions of high shear.

5. A container as claimed in any one of claims 1 to 4 having a closure through which the contents of the container are dispensed, said closure being formed from said thermoplastic material containing said anti-microbial preservative.

6. A container as claimed in any one of claims 1 to 5, further including a shoulder piece having a dispensing nozzle, the shoulder piece being formed from said thermoplastic material including said anti-microbial preservative.

7. A container as claimed in any one of claims 1 to 6 wherein the container comprises a flexible tubular body formed from a laminate comprising a plurality of layers of thermoplastic material, wherein at least one layer of the laminate includes said thermoplastic material containing said anti-microbial preservative.

8. A container as claimed in claim 7 wherein said one layer is the inner-most layer relative to the interior of the tube.